Automated and semi-automated manufacturing processes are being used increasingly in the production of wind turbine components such as wind turbine blades. Examples of such processes include the application of gel coats to moulds, the layup of fibrous materials in the moulds and the application of adhesive to moulded parts.
A prior art production system for a wind turbine blade is illustrated schematically in the plan view of FIG. 1. Referring to FIG. 1, the system comprises an elongate mould assembly 10 in which a half shell 12 of a wind turbine blade is formed. The mould assembly 10 comprises a female mould 14 defining a generally concave mould surface 16, which is surrounded by a generally flat mould flange 18. The mould assembly 10 tapers inwardly moving from a root end 20 to a tip end 22, such that the tip end 22 of the mould assembly 10 is considerably narrower than the root end 20.
Walkways 24 in the form of platforms are provided alongside the mould assembly 10. The walkways 24 are raised significantly off the ground and are utilised extensively by personnel during the production of the blades to facilitate inspection of, and access to, the mould surface 16 and the surrounding flange 18.
A pair of parallel tracks 26 extends longitudinally along the factory floor on respective longitudinal sides of the mould assembly 10. The tracks 26 are provided outboard of the walkways 24 and at a sufficient distance from the mould assembly 10 to allow space for the walkways 24. A transport assembly 28 is arranged on the tracks 26. The transport assembly comprises a gantry 30, which extends in a transverse direction above the mould assembly 10. The gantry 30 is supported by a pair of vertical side supports 32, which are arranged respectively on opposite longitudinal sides of the mould assembly 10. The side supports 32 are provided on the tracks 26, and the transport assembly 28 is configured to travel along the tracks 26 to move the gantry 30 above the mould 14 in a longitudinal direction L.
A robot 34 having a suitable application device is mounted on the gantry 30 above the mould 14. The robot 34 is arranged to move in a transverse direction T along the gantry 30. The robot 34 may also be arranged to move vertically relative to the mould 14 and may have additional rotational degrees of freedom, for example a six-axis gantry robot. An example of an automated production system is described in WO2011/035539A1.
Referring to FIG. 2, wind turbine blades are typically formed from two half shells 12a, 12b, which are manufactured separately in two side-by-side female moulds 14a, 14b. Once the half-shells 12a, 12b have been moulded, adhesive is applied along the leading edges 15a, 15b and trailing edges 17a, 17b of the shells 12a, 12b, and one of the moulds is lifted, turned and arranged on top of the other mould to bond the half-shells 12a, 12b together to form the complete blade. A lifting and turning mechanism 36 is provided between the moulds 14a, 14b for this purpose.
The blades for the latest generation of utility-scale wind turbines are around eighty meters in length and have a root diameter of around five meters. It will therefore be appreciated that the mould assemblies described above are very large. In view of the large size of the moulds, it will be appreciated that the automated production systems described above and in WO2011/035539A1 are expensive to produce and occupy a considerable amount of factory floor space. Careful design considerations must also be employed to ensure that the tracks between the mould assemblies do not interfere with the lifting and turning mechanism 36 provided in this region, and vice versa.
There is a continuing drive to reduce the cost of manufacturing processes, and factory floor space is also at a premium. Against this background, the present invention aims to provide a more compact and inexpensive production facility for the manufacture of wind turbine blades.